Effect of ferrostatin-1 on living myocardial slices derived from heart failure patients

Cardiac injury remains a leading cause of death globally with limited availability of therapeutic approaches. In this study, we employed living myocardial slices (LMS) as an ex vivo model of cardiac injury to investigate underlying mechanisms and potential therapeutic targets. Cryoinjury was induced in adult rat LMS, resulting in 30% tissue damage. Cryoinjured LMS demonstrated impaired contractile function, cardiomyocyte hypertrophy, inflammation, and cardiac fibrosis, closely resembling in vivo cardiac injury characteristics. Proteomic analysis revealed an enrichment of factors associated with ferroptosis in the injured LMS, suggesting a potential causative role. To test this hypothesis, we pharmacologically inhibited ferroptosis using ferrostatin (Fer-1) in the cryoinjured rat LMS, resulting in attenuation of structural changes and repression of pro-fibrotic processes. Furthermore, LMS generated from failing human hearts were used as a model of chronic heart failure. In this model, Fer-1 treatment was observed to reduce the expression of ferroptotic genes and enhance contractile function. Blocking ferroptosis in human cardiac fibroblasts (HCFs) resulted in a downregulation of fibroblast activation genes, a decrease in fibroblast migration capacity, and a reduction in reactive oxygen species production. Analysis of RNA sequencing data from Fer-1-treated human LMS revealed that metallothioneins, a group of cysteine-rich proteins recognized for their antioxidative attributes and capacity to neutralize free radicals and reactive oxygen species, might serve as a potential mechanism underlying the suppression of ferroptosis. This effect is likely to be mediated by replenishing the existing glutathione reserves within the cells, which are then harnessed to combat lipid peroxidation and ferroptosis. These findings highlight the potential of targeting ferroptosis and metallothioneins as a promising strategy for the treatment of heart disease.